REPAIRING AND NOT THROWING AWAY

REPAIRING AND NOT THROWING AWAY

Richtige Fernseher haben Röhren!

Richtige Fernseher haben Röhren!

In Brief: On this site you will find pictures and technical information about Service Modes, Circuit Diagrams, Firmware Update procedure, Disassemble procedure, Universal remote control set-up codes, Troubleshooting and more....

If you go into the profession, you will obtain or have access to a variety of tech tips databases HERE IT IS Master Electronics Repair !.

These are an excellent investment where the saying: 'time-is-money' rules. However, to learn, you need to develop a general troubleshooting approach - a logical, methodical, method of narrowing down the problem. A tech tip database might suggest: 'Replace C536' for a particular symptom. This is good advice for a specific problem on one model. However, what you really want to understand is why C536 was the cause and how to pinpoint the culprit in general even if you don't have a service manual or schematic and your tech tip database doesn't have an entry for your sick TV or VCR.

While schematics are nice, you won't always have them or be able to justify the purchase for a one-of repair. Therefore, in many cases, some reverse engineering will be necessary. The time will be well spent since even if you don't see another instance of the same model in your entire lifetime, you will have learned something in the process that can be applied to other equipment problems.
As always, when you get stuck, checking out a tech-tips database may quickly identify your problem and solution.In that case, you can greatly simplify your troubleshooting or at least confirm a diagnosis before ordering parts.

Happy repairing!
Today, the West is headed for the abyss. For the ultimate fate of our disposable society is for that society itself to be disposed of. And this will happen sooner, rather than later.

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..............The bitterness of poor quality is remembered long after the sweetness of todays funny gadgets low price has faded from memory........ . . . . . .....
Don't forget the past, the end of the world is upon us! Pretty soon it will all turn to dust!

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All posts are presented here for informative, historical and educative purposes as applicable within fair use. NOTHING HERE IS FOR SALE !

Wednesday 27 March 2019

LG PLASMA 42PJ350 _ POWER SUPPLY _ STATIC TEST

LG PLASMA 42PJ350 _ POWER SUPPLY _ STATIC TEST





POWER SUPPLY VOLTAGE CHECK

WARNING: Remove AC when adding or removing any plug or resistor.

TEST CONDITIONS
  • Connector going to the Y-SUS P811 is disconnected. P301 on the Main board disconnected (coming in on P813). Use the holes on the connector P301 (Main Board side) to insert the resistors or jumper leads. Connect (2) 100 Watt light bulbs in series between VS and Ground.
  • When the supply is operational in its normal state the Auto Ground line at Pin 18 of P813 is held at ground by the Main Board. This Power Supply can be powered on sequentially to test the Controller Chip IC701 operational capabilities and for troubleshooting purposes. By disconnecting P301, pin 18 is opened. To return the SMPS to the normal state for this test procedure, this pin must be grounded.
Note: Leave previous installed 100Ω resistor in place when adding the next resistor.
  1. Ground the Auto Gnd Line (Pin 18) will allow the supply to be powered up one section at a time.
  2. Add a 100Ω ¼ watt resistor from 5V Standby to RL_ON and the 17V and 5V Run Lines on P813 will become active. Also AC-Det and Error_Det will go high.
  3. Add a 100Ω ¼ watt resistor from any 5V line to M_ON (Monitor On) to make the M5V, VS and VA lines operational. P811 (VS pins 1 and 2) (VA pins 6 and 7) and the (M5V pins 9 and 10).




SMPS connector P813 identification / voltages and diode check

P813 Connector “SMPS" to “Main" P301

PIN
LABEL
STBY
RUN
NO LOAD
DIODE
1~2
17V
0V
16.8V
16.79V
OPEN
3~4
GND
GND
GND
GND
GND
5~7
5V
0.47V
5.24V
5.25V
1.29V
8
ERROR_DET
2.88V
4.93V
4.91V
2.96V
9~12
GND
GND
GND
GND
GND
13~14
STBY 5V
3.49V
5.23V
5.25V
2.43V
15
RL_ON
0V
2.43V
0V
OPEN
16
AC DET
0V
4.5V
4.93V
2.95V
17
M_ON
0V
3.27V
0V
OPEN
18
AUTO_GND
GND
GND
4.84V
2/34V






Notes:
  1. The 17V, 5V, AC_Det and Error Det turn on when the RL_On commandarrives.
  2. The M5V, Va and Vs turn on when the M_On (Monitor On) command arrives.
  3. The Error Det line is not used in this model.
  4. If the AC Det line is Missing, the TV will shut off after 10 seconds of operation.
  5. Pin 18 is grounded on the Main board. If this line is floated, the SMPS turns on Automatically when AC is applied.
Diode Mode Readings taken with all connectors Disconnected. 
DVM in Diode Mode.

Posted By: FRANK at 02:25
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